Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
STILBETIN vs DIVIGEL
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: June 2026 · OpiCalc Medical Review Team
Diethylstilbestrol (STILBETIN) is a nonsteroidal estrogen that binds to estrogen receptors, activating estrogen-responsive genes, leading to increased synthesis of proteins involved in growth and differentiation of female reproductive tissues.
Estradiol replacement therapy; binds to estrogen receptors, activating transcription of estrogen-responsive genes, leading to proliferation of endometrial and breast epithelium, and modulation of gonadotropin secretion.
Treatment of advanced prostate cancer (androgen-dependent),Estrogen replacement therapy (formerly),Prevention of post-partum breast engorgement (formerly),Palliative therapy for breast cancer in selected patients
Treatment of moderate to severe vasomotor symptoms due to menopause,Treatment of moderate to severe symptoms of vulvar and vaginal atrophy due to menopause,Prevention of postmenopausal osteoporosis (for women with significant risk, when non-estrogen medications are not appropriate)
25 mg orally 3 times daily for 5 days; repeat if necessary after 1 month.
Transdermal gel: 0.25-1.0 g applied once daily to upper thigh, abdomen, or upper arm. Each gram contains 1 mg estradiol.
Terminal elimination half-life is approximately 1-2 hours (range 1-3 h) for estradiol; clinical relevance: requires multiple daily dosing (e.g., 3-4 times/day) for sustained effect.
Terminal elimination half-life of estradiol is 13-15 hours; clinical context: due to enterohepatic recirculation, serum levels may fluctuate; transdermal delivery avoids first-pass hepatic metabolism, resulting in more stable levels
No dose adjustment required for mild to moderate impairment. For severe impairment (GFR <30 m L/min), use with caution and consider reducing dose by 50%.
No specific dose adjustment recommended based on GFR; estradiol is not significantly renally cleared.
Contraindicated in Child-Pugh class C cirrhosis. For Child-Pugh class A or B, reduce dose by 50% and monitor liver function.
There is an increased risk of endometrial cancer in postmenopausal women using estrogens. STILBETIN is contraindicated in women with known or suspected pregnancy due to risk of vaginal adenosis and clear cell adenocarcinoma in female offspring exposed in utero.
STILBETIN (diethylstilbestrol) is a known transplacental carcinogen and teratogen. First trimester exposure causes vaginal clear cell adenocarcinoma in female offspring (0.1-0.4%) and genital tract malformations. Second/third trimester exposure risks preterm labor, fetal demasculinization in males, and Mullerian anomalies. Contraindicated in pregnancy.
Divigel (estradiol) is contraindicated in pregnancy. Estrogens are associated with an increased risk of congenital anomalies, including cardiovascular and urogenital defects, when used during the first trimester. In the second and third trimesters, exposure may cause feminization of male fetuses, functional genital tract abnormalities, and potential long-term reproductive effects. Use is not recommended at any stage.
STILBETIN (diethylstilbestrol) is a nonsteroidal estrogen used historically for pregnancy support but now contraindicated due to teratogenicity and increased cancer risk. Monitor for thromboembolic events, vaginal adenocarcinoma in offspring. Use only in select cases like prostate cancer or lactation suppression.
Divigel (estradiol gel) is a transdermal estrogen therapy for moderate-to-severe vasomotor symptoms of menopause. Apply to clean, dry, non-irritated skin on upper thigh or calf, rotating sites daily. Do not apply to breasts or genital area. Avoid sun exposure or heating pads over application site. Monitor for endometrial hyperplasia; add progestin if uterus intact.
No interactions on record
No interactions on record
Common clinical questions about STILBETIN vs DIVIGEL, answered by our medical review team.
STILBETIN is a Estrogen that works by Diethylstilbestrol (STILBETIN) is a nonsteroidal estrogen that binds to estrogen receptors, activating estrogen-responsive genes, leading to increased synthesis of proteins involved in growth and differentiation of female reproductive tissues.. DIVIGEL is a Estrogen that works by Estradiol replacement therapy; binds to estrogen receptors, activating transcription of estrogen-responsive genes, leading to proliferation of endometrial and breast epithelium, and modulation of gonadotropin secretion.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between STILBETIN and DIVIGEL depend on the specific clinical indication. These are both Estrogen agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of STILBETIN is: 25 mg orally 3 times daily for 5 days; repeat if necessary after 1 month.. The standard adult dose of DIVIGEL is: Transdermal gel: 0.25-1.0 g applied once daily to upper thigh, abdomen, or upper arm. Each gram contains 1 mg estradiol.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between STILBETIN and DIVIGEL in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. STILBETIN is classified as Category C. STILBETIN (diethylstilbestrol) is a known transplacental carcinogen and teratogen. First trimester exposure causes vaginal clear cell adenocarcinoma in female offspring (0.1-0.4%) . DIVIGEL is classified as Category C. Divigel (estradiol) is contraindicated in pregnancy. Estrogens are associated with an increased risk of congenital anomalies, including cardiovascular and urogenital defects, when . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.
Hepatic metabolism via hydroxylation and glucuronide conjugation; undergoes enterohepatic recirculation.
Primarily hepatic metabolism via CYP3A4; also undergoes conjugation (glucuronidation) and sulfation; enterohepatic recirculation.
Primarily renal as glucuronide and sulfate conjugates; approximately 50-80% of a parenteral dose excreted in urine within 24 hours; 10-20% via bile into feces.
Urine (approximately 90-95% as glucuronide and sulfate conjugates, with less than 5% as unchanged drug); feces (approximately 5-10% via biliary excretion)
~98% bound primarily to sex hormone-binding globulin (SHBG) and albumin.
98-99% bound primarily to sex hormone-binding globulin (SHBG) and albumin
Vd approximately 0.5-1 L/kg (estradiol); distributes widely into tissues with high lipid content.
Vd approximately 1-2 L/kg, indicating extensive distribution into tissues; clinical meaning: reflects wide distribution to target organs such as breast, uterus, and adipose tissue
Oral: very low (<5%) due to extensive first-pass hepatic metabolism; parenteral (IV/IM): 100% (by definition).
Transdermal gel: approximately 10-20% of the applied dose (due to incomplete absorption and retention in the skin depot); avoids first-pass hepatic metabolism, thus effective at lower doses compared to oral
Contraindicated in severe hepatic dysfunction (Child-Pugh class C). In mild to moderate (Child-Pugh A/B), use with caution and monitor.
Weight-based dosing: 0.5 mg/kg/day orally divided every 8 hours for 5 days; maximum 25 mg per dose.
Not FDA-approved for use in children; efficacy and safety not established.
Start at lowest effective dose (e.g., 12.5 mg 3 times daily) and titrate cautiously due to increased risk of adverse effects; monitor renal function.
Use lowest effective dose; consider increased risk of thromboembolic events, cardiovascular disease, and dementia in women >65 years.
Estrogens increase the risk of endometrial cancer in women with an intact uterus. Estrogen-alone therapy should not be used for the prevention of cardiovascular disease or dementia. Increased risk of venous thromboembolism, stroke, and possibly dementia. Estrogen plus progestin has been associated with increased risk of breast cancer, stroke, VTE, and dementia.
Increased risk of thromboembolic events, stroke, myocardial infarction, and pulmonary embolism; increased risk of endometrial cancer; caution in patients with cardiovascular disease, hepatic impairment, or history of thromboembolic disorders; may exacerbate fluid retention and hypertension.
Cardiovascular disorders (e.g., coronary heart disease, stroke, VTE), malignant neoplasms (endometrial cancer, breast cancer), gallbladder disease, hypercalcemia, fluid retention, elevated blood pressure, hereditary angioedema, hypertriglyceridemia, hepatic hemangiomas, exacerbation of endometriosis, severe hypocalcemia in hypoparathyroidism, and thyroid hormone effects.
Known or suspected pregnancy; known or suspected breast cancer (except in selected metastatic cases); known or suspected estrogen-dependent neoplasia; active thromboembolic disorders or history of such; undiagnosed abnormal genital bleeding; known hypersensitivity to diethylstilbestrol.
Undiagnosed abnormal genital bleeding; known, suspected, or history of breast cancer; known or suspected estrogen-dependent neoplasia; active or history of venous thromboembolism; active or history of arterial thromboembolism; known anaphylactic reaction or angioedema to estradiol; known liver impairment or disease; known protein C, protein S, or antithrombin deficiency; known thrombophilic disorders; pregnancy; hypersensitivity to any ingredient.
Grapefruit and grapefruit juice may increase diethylstilbestrol levels. Avoid alcohol as it may increase estrogen levels. Calcium-rich foods may reduce absorption; separate by 2 hours.
No significant food interactions. Grapefruit juice may increase estradiol exposure; avoid excessive intake.
STILBETIN is excreted in human milk; M/P ratio approximately 1.0. Potential for serious adverse effects in nursing infant. Breastfeeding not recommended due to estrogen exposure and long-term carcinogenic risk.
Estradiol is excreted into human breast milk in small amounts. The M/P ratio is not specifically reported for Divigel; however, estradiol levels in milk are low. Effects on the nursing infant are not well studied, but potential for adverse effects exists. Divigel is not recommended during breastfeeding.
STILBETIN is contraindicated in pregnancy due to teratogenicity; no dose adjustment is applicable. If exposure occurs, immediate discontinuation and specialist consultation for fetal risk assessment.
Divigel has no approved use in pregnancy; dose adjustments are not applicable. Use is contraindicated.
This medication is a synthetic estrogen with serious risks including cancer and blood clots.,It must not be used during pregnancy as it causes severe birth defects.,Report any unusual vaginal bleeding, breast lumps, or leg swelling immediately.,Regular gynecologic exams are required due to increased cancer risk.,Do not take with other hormonal medications without consulting your doctor.
Apply gel at the same time each day to clean, dry skin on upper thigh or calf. Rotate application sites daily.,Do not apply to breasts, face, or genital area. Avoid contact with others until gel dries (about 5 minutes).,Wash hands thoroughly after application. Avoid water, sunscreen, or lotion on the application site for 2-3 hours.,Report unusual vaginal bleeding, breast lumps, leg pain, or jaundice immediately.,Do not smoke or use nicotine products while on estrogen therapy.